I switched to digital about a year ago after 25 years of slides. I'm finding the business of slide shows to be a problem. I first tried to export a show from Lightroom and project it via a laptop and S video on our 42" plasma. The resolution was awful. Next, I loaded Lightroom on the laptop and used its slideshow mode, again resolution on the plasma was awful and the colors were beyond garish. I've finally hooked up the laptop and tested it with a small digital projector (800 x 600). The results were somewhere between satisfactory and good. The images are still slightly blurred relative to my monitor, but probably acceptable for most viewers. In other posts in this forum, I've seen it suggested that the images need to be reduced in resolution, but that requires exporting to photoshop and reimporting. Are there other solutions to this problem?

I did some tests years ago on an Epson projector with a projection distance of about 15-20 ft. I found that 72 ppi images were too soft and 150 ppi was much better. Going up to 300 ppi didn't look any better than 150. By the way, I don't remember what the projectors resolution was. That will make a difference as well. The best thing to do is try some different resolutions out using the same image and the view/projection distance you think you'll use.

The resolution of the image should be exactly the same as the resolution of the output device if viewing in full screen.

So if you have an 800x600 projector, convert your image to 800x600 (or within those confines - 800x500 is fine, for example).

The DPI is meaningless.

What you don't want to happen is to have the projector/TV etc rescale your image for you - you need to do that ahead of time.

Also, ideally you want a digital connection between the computer and the output device (DVI -> HDMI for example).

Finally, you need to check the colour and other adjustments on the output device. Again, ideally, you would calibrate it but if you can't, try setting everything back to default. Any changes you may have made on the plasma to improve the image for viewing televsion is probably working against obtaining the best quality for still images.

Finally, since your TV or projector will at best provide an sRGB (or thereabouts) gamut, you need to ensure your images are in such a space.